A constant velocity universal joint used for power transmission in automobiles and various industrial machines has a bellows boot mounted thereon so as to prevent intrusion of foreign matter such as dust into the joint and leakage of grease sealed inside the joint. As a material for the constant velocity universal joint boot, there are well-known a silicone material, a CR material (chloroprene), a VAMAC material (ethylene-acrylic rubber), and a CM material (chlorinated polyethylene).
Examples of the boot band include what is called a one-touch band. As illustrated in FIG. 22, a boot band 1 called one-touch band is obtained by curving a band member 2 made of a belt-like metal material into a ring shape, and coupling both ends thereof to each other in an overlapping manner. A lever 4 is firmly fixed to one side of an overlapping portion 3 of the band member 2.
The boot band 1 is mounted to a boot as follows. First, the band member 2 having the ring shape is fitted loosely to an outside of a boot mount portion of the boot. In this state, the lever 4 is folded back as indicated by an arrow α by utilizing leverage. In this way, the band member 2 fitted to the boot mount portion of the boot is radially shrunken to fasten the mount portion of the boot. Note that, an end portion of the lever 4 thus folded back is latched to a stopper 5 arranged near the overlapping portion 3.
In conventional cases, generally, an operator manually positions the boot band 1 described above, and then clamps the stopper 5 with jigs and tools such as a hammer. In such a case, work hours and quality may vary due to differences of the skill level of the operator. As a countermeasure, as described, for example, in Patent Literature 1, there have been proposed devices for automatically fastening such stopper 5.
Further, the boot band includes what is called an omega band as illustrated in FIG. 23. Also in this case, a belt-like member 9 is looped into a ring shape, fitted to an outside of the band mount portion of the boot, and then radially shrunken. Specifically, the belt-like member 9 includes engagement holes 6 provided at a part that come to an outer side of the overlapping portion, and protrusions 7 that come to an inner side of the overlapping portion when the belt-like member 9 is looped into a ring shape.
Then, the protrusions 7 are engaged with the engagement holes 6 from a radially inner side. In this state, a force of reducing a circumferential length is applied. In order to apply the reduction force, a fastening lobe portion (projection portion having a rectangular shape in cross-section) 8 provided at the part that comes to the outer side of the overlapping portion is plastically deformed (clamped). Specifically, clamping is performed by applying a pressing force as indicated by arrows β and β to the projection portion 8 illustrated by imaginary lines in a manner that proximal side walls thereof are brought close to each other. As described, for example, in Patent Literature 2, there have been proposed a device for clamping the projection portion 8.
Further, examples of the band include a low profile band as described, for example, in Patent Literature 3. This band is obtained by looping a belt-like member 151 as illustrated in FIG. 24 into a ring shape as illustrated in FIG. 25, and being fitted to the outside of the mount portion of the boot.
The belt-like member 151 includes, on its one end portion side, a protruding portion 152 provided to project to a front surface side, a claw portion 153 provided near the protruding portion 152, and protruding portions 154 and 155 provided near the claw portion 153 so as to project to the front surface side. Further, the belt-like member 151 includes, on its another end portion side, a rectangular engagement hole 156, and an elongated hole 157 provided near the engagement hole 156. In addition, on an opposite side with respect to the engagement hole of the elongated hole 157, a protruding portion 158 is provided to project to the front surface side.
Description is made of a method of fixing a boot with use of this band. First, as illustrated in FIG. 25A, the belt-like member 151 is looped into a ring shape so as to fit the protruding portion 152 to the elongated hole 157. In other words, a ring portion 159 is formed, and fitted loosely to the outside of the band mount portion of the boot. In this case, the protruding portion 152 is arranged on the engagement hole 156 side in the elongated hole 157.
After that, the protruding portion 158 and the protruding portion 152 are nipped with a tool 160 described below (refer to FIG. 26). In this state, the tool 160 is operated to bring the protruding portion 152 and the protruding portion 158 close relative to each other as illustrated in FIG. 25B. With this approach, the ring portion 159 is gradually radially shrunken. Then, as illustrated in FIG. 25C, under a state in which the protruding portion 152 and the protruding portion 158 are held in contact with each other, the protruding portion 155 is engaged with the engagement hole 156, and the protruding portion 154 is engaged with the engagement hole 156 side of the elongated hole 157. In this way, the band fastens the band mount portion of the boot, and the boot can be firmly fixed to an outer joint member of a constant velocity universal joint, and to a shaft fitted into an inner joint member of the constant velocity universal joint.